Device for feeding a treatment liquid to medical appliances

ABSTRACT

A device for feeding a treatment liquid into medical appliances. The device includes an outlet opening for the treatment liquid, especially for feeding water into dental equipment, a feed line for the treatment liquid, means to introduce degerminating agents into the treatment liquid, and an on/off valve disposed upstream from an outlet opening onto which the feed line is connected. A back-flush valve is connected to the on/off valve, and a reservoir is provided for the treatment liquid, whereby the treatment liquid is transported from the reservoir with the aid of a pump. Further, a back-flush line is connectible alternatively via a drain valve to a drain or to the reservoir so that the treatment liquid is pumped into the drain, or in circulation from the reservoir through the feed line to the switch valve and through the back-flush line again into the reservoir.

The invention relates to a device for feeding a treatment liquid tomedical appliances comprising an outlet opening for the treatmentliquid, especially for feeding water into dental equipment, and a feedline for the treatment liquid as well as means for introducingdegerminating agents into the treatment liquid.

Medical appliances are well known in practice to be used in differentapplications through which a treatment liquid is applied. Microbialcontamination of the treatment liquid is to be absolutely prevented,especially in the medical field. Problems occurring in this connectionare described below in an example of a dental treatment unit—a so-calleddental equipment having a cooling liquid supply and an irrigation liquidsupply.

As a rule, dental equipment uses drinking water as cooling andirrigation liquid that is drawn from the local water supply net. Even atthe connection point of the drinking water supply and the dentalequipment, there is often found a bacteria count that is far above thelimit of 100 colony-forming units per milliliter (KBE/ml) determined bythe drinking water ordinance and there are often times detectedproblematic bacteria such as “Pseudomonas aeruginosa” or “Legionella”.In addition, dental treatment units have particular features in contrastto the drinking water system, which promote bacteria growth and causes ahigh bacteria count thereby.

Dental treatment units include normally a plurality of handpieces withdifferent treatment adapters whereby each handpiece is connected to anindividual tap. Often times, water remains in the treatment unit for arelative long time based on the different use of the individualhandpieces, during breaks in treatment, and during the weekend, whichcauses stagnation of water. Standing water is thereby warmed up to roomtemperature. In addition, water is brought to body temperature beforethe application. Bacteria growth is promoted further by small hoses,constrictions in cross sections and formation of dead space, e.g. invalves. Additionally, it must be considered that most of thewater-conducting components and hoses of dental treatment units are madeof synthetic material whereby they provide an ideal nutritive medium forbacteria growth because of the large surface per water volume.

Sterilization of the drinking water before application is thereforeadvisable or even absolutely necessary. Sterilization units or measuresare employed in practice which introduce either a suitable degerminating(antimicrobial) agent into the drinking water at a particular dosage orwhich cause sterilization through an electrolytical process, forexample.

It has been shown, however, that bacteria growth cannot be completelyprevented with the aid of sterilization units of the prior art sincebacteria growth increases in the line at a distance away from thesterilization unit. Overall, re-contamination cannot be reliablyprevented with the use of sterilization units of the prior art.

Some manufacturers of dental equipment offer therefore so-calledconditioning programs. In the scope of these conditioning programs,highly concentrated degerminating agents are pumped through the entiredental equipment, through each outlet and each handpiece, and they arethen left in the lines of the dental equipment for several hours. Thedental equipment is subsequently flushed with drinking water until theconcentration of the degerminating agent is reduced to a level that isharmless for the patient.

Completion of a conditioning program, as described above, normally takes12 to 24 hours during which time the dental equipment cannot be used.Re-contamination can be effectively prevented only by regular use of theabove-mentioned program since there is currently no possibility todetermine the degree of microbial contamination of the dental equipmentand to discern if conditioning is actually necessary.

In the German laid-open patents 32 46 266 and 36 35 568 are discloseddevices for the disinfection of water paths in dental appliancesproviding periodic flushing of the water paths with a disinfectant. Inboth cases, there are feed lines provided for the treatment liquid andmeans to introduce degerminating agents into the treatment liquid.Valves are assigned to the outlet opening in the feed line of thedisclosed arrangement.

The object of the German laid-open patent 195 09 180 A1 is anarrangement to clean at least one so-called drive pathway in a medicalhandpiece, particularly a dental handpiece. In this arrangement thereare valves provided for each of the feed lines. In addition, there is aspecial non-return valve arranged in a connecting line.

The object of U.S. Pat. No. 5,087,198 is a dental appliance into which atreatment liquid can also be fed. This appliance comprises three-wayvalves disposed upstream for switching the treatment liquids.

SUMMARY OF THE INVENTION

The inventive device achieves the above object through thecharacteristics of patent claim 1. Accordingly, the aforementioneddevice is designed in a manner whereby an on/off valve is disposedupstream of the outlet opening onto which the feed line is connected,and whereby a back-flush line with a back-flush valve is connected tothe on/off valve.

The present invention has now the object to provide a device for feedinga treatment liquid into medical appliances of the aforementioned typewith which microbial contamination or re-contamination can be preventedin a simple but effective manner.

The inventive device achieves the above object through thecharacteristics of patent claim 1. Accordingly, the aforementioneddevice is designed in a manner whereby a switch valve is disposedupstream of the outlet opening onto which the feed line is connected,and whereby a back-flush line with a back-flush valve is connected tosaid switch valve.

According to the invention, it has been observed that re-contaminationcan be effectively prevented with the use of sterilization units of theprior art if the treatment liquid, which is fed through the medicalappliance and which is then enriched with a degerminating agent, is notnecessarily dispensed via the outlet opening of the medical appliancebut can be used alternatively for flushing of the medical appliance. Forthis purpose, an on/off valve is placed upstream of the outlet opening,according to the invention, onto which there is connected the feed lineas well as a back-flush line with its back-flush valve so that the feedline can be alternatively connected to the outlet opening or theback-flush line. The treatment liquid, which is enriched withdegerminating agents, flows through the feed line up to the switch valveand via the switch valve into the back-flush line to flush the medicalappliance. Thereby the back-flush valve is opened.

Since the treatment liquid enriched with degerminating agents can beeither simply applied through the outlet opening, based on theinventively proposed constructive measures, or be used for flushing ofthe appliance, there is also the possibility to flush the medicalappliance according to needs, e.g. directly before application of thetreatment liquid, during treatment breaks, or before daily operationaluse.

The valve concept of the inventively proposed device for feeding atreatment liquid may be basically realized with the use of various typesof valves.

The on/off valve and the back-flush valve may thereby be designed asone, which means as a three-way valve disposed upstream from the outletopening, with which either the outlet opening or the back-flush line canbe selectively connected to the feed line.

In most medical appliances and particularly in dental equipment, thepossibly smallest instrument size should be the goal, especially theregion of the outlet opening in which the on/off valve is arranged. Itis of advantage thereby to arrange the back-flush valve in theback-flush line itself, which means offset relative to the on/off valve.A pressure-controlled valve can be used in this case as a on/off valvethat closes and opens, depending on the switched position of theback-flush valve in the back-flush line and the thereby associatedpressure conditions in the back-flush line. In contrast to other typesof valves, e.g. electrical on/off valves, there are no additionalcontrolling means necessary, such as wires etc, which would have anegative impact on the size of the on/off valve.

It is of great advantage to realize the on/off valve as a non-returnvalve. Reverse suction via the outlet opening can be prevented thereby,including the associated infiltration of fluid and bacteria into themedical appliance.

As mentioned above, the inventive device for feeding a treatment liquidinto medical appliances comprises means to introduce degerminatingagents into the treatment liquid whereby this could be a sterilizationunit already well known in practice. In an especially preferredembodiment of the inventive device there are provided additional meansfor determining the type and/or amount of bacteria existing in thetreatment liquid or in the medical appliance so that there can bedetermined, on an individual basis, the type and dosage of thedegerminating agent to be added as well as the back-flush period. Inaddition, means can be provided to determine the concentration orpossibly the type of degerminating agent in the treatment liquid so thatthe dosage of the degerminating agent added to the treatment liquid canbe monitored or possibly also controlled. It can be easily determinedthereby whether the degerminating agent has been used up by consumptionduring a period of standstill. Should there be means provided toregulate the concentration of the degerminating agent in the treatmentliquid, then the medical appliance can also be directly flushed withtreatment liquid that has a degerminating agent added at a higherconcentration than the one that is proposed for application.

It is furthermore advantageous to provide a reservoir for the treatmentliquid and to transport the treatment liquid with the aid of a pump fromthe reservoir. In this case, the treatment liquid could be enriched inthe reservoir with at least one degerminating agent with the aid of adosage device assigned to the reservoir so that an additionalsterilization unit would not be needed in the feed line. An additionalsterilization unit disposed upstream from the reservoir would have theadvantage that the reservoir as well as the pump could be sterilizedtogether. A sterilization unit of this type could also be used as analternative to the dosage device assigned to the reservoir.

The back-flush line is alternatively connectable via a drain valve to adrain or to the reservoir in the inventive device so that the treatmentliquid can be pumped alternatively into the drain during flushing of themedical appliance or it can be pumped in circulation from the reservoirthrough the feed line to the on/off valve—and via the back-flush lineagain into the reservoir. The possibility to pump the treatment liquidenriched with degerminating agents in circulation through the device andthe medical appliance is especially advantageous when a flushing processis necessary with higher concentrated degerminating agents.

One should be able to empty the reservoir directly in an advantageousmanner to flush sediments from the reservoir, for example. In apreferred embodiment of the inventive device, there could be provided adrain valve for this purpose.

BRIEF DESCRIPTION OF THE DRAWING

There are now various possibilities to design and develop the device inan advantageous manner according to the theory of the present invention.This is shown, on one hand, in the subordinate claims of patent claim 1,and, on the other hand, in the following description of an embodiment ofthe invention and with the aid of the drawing.

The single drawing shows in a schematic illustration a device accordingto the invention for feeding water into a dental treatment unit.

The dental treatment unit (not further identified in the single drawing)is thereby connected via a feed line 2 to the local drinking watersupply 3—and the individual hand pieces or the dental instruments 1 areconnected parallel to the feed line 2 via assigned supply valves 4 andfeed line sections 2 a.

In the hereby illustrated embodiment, the drinking water drawn from thewater supply 3 passes through a sterilization unit 5 arranged in thefeed line 2, wherein it is enriched with a degerminating agent, and thenflows into a reservoir 6. From there, the liquid is urged with the aidof a pump 7 through an additional sterilization unit 8 to the individualdental instruments 1.

DETAILED DESCRIPTION OF THE INVENTION

In the drawing, the dental treatment unit has three handpieces fordifferent dental instruments 1. Each of these dental instruments 1 isprovided with an outlet opening through which water may be applied as acooling and/or irrigation liquid during treatment of a patient.Accordingly, the dental instruments 1 must be supplied with water atleast during the treatment of the patient.

According to the invention, an on/off valve 9 is disposed upstream fromthe outlet opening of each dental instrument 1 whereby the feed line 2or the respective feed line section 2 a is connected to valve 9. Aback-flush line 10 a, 10 together with a back-flush valve 11 isconnected to the switch valve 9 in addition to the feed line 2.

According to the illustrated embodiment, the on/off valves 9 of theindividual dental instruments 1 are very near to the respective outletopening so that each dental instrument 1 has its own back-flush linesection 10 a running parallel to the respective feed line section 2 a inthe assigned handpiece hose. The back-flush line sections 10 a of theindividual dental instruments 1 are then connected to a mutualback-flush line 10 in which the back-flush valve 11 is arranged as well.Alternatively thereto, a back-flush valve of the respective dentalinstrument could also be arranged in each back-flush line section 10 a.

The on/off valves 9 of the individual instruments 1 are here designed asnon-return valves so that suction of liquid through the outlet openingof a dental instrument 1 is prevented and thereby prevented is therebyalso the associated migration of bacteria into the treatment unit. Inaddition, the valves 9 in the illustrated embodiment are all pressurecontrolled. The switched position of the valves 9 depends here also onthe switched position of the supply valve 4 of the respective dedicateddental instrument 1, on the one hand, and on the switched position ofthe back-flush valve 11, on the other hand. At first, the respectivesupply valve 4 is opened at employment of one of the three existingdental instruments. While the back-flush valve 11 is simultaneouslyclosed, a back pressure develops in the back-flush line 10 or in theback-flush line section 10 a of the dental instrument 1, which in turneffects the opening of the assigned valve 9 so that the water can beapplied through the outlet opening of the dental instrument 1. Shouldthe back-flush valve 11 also be opened while the supply valve 4 is open,then the switch valve 9 closes automatically. The water enriched withdegerminating agents is then pumped through the feed line 4 into thedental instrument 1 and up to the valve 9 and then the liquid flows fromthere through the back-flush line 10 a, 10, the back-flush valve 11 andthe drain valve 12 alternatively either into the drain 13 or back intothe reservoir 6—depending on the switched position of the drain valve13—from where the liquid can be pumped again in circulation to thedental instrument 1 and back into the reservoir 6. This flushing processcan then be repeated as often as desired whereby the supply of waterenriched with degerminating agents is pumped continuously at setintervals through the line system of the treatment unit.

The reservoir 6 is additionally provided with an overflow 14 in theillustrated embodiment example, which also leads to the drain 13. Thereservoir 6 can be emptied directly into the drain 13 through a drainvalve 15.

Finally, there is still a measuring probe 16 arranged in the feed line 2between the sterilization unit 5 and the reservoir 6, which serves todetermine the concentration and possibly the type of degerminating agentin the treatment liquid so that the dosage of the degerminating agentinfused in the treatment liquid can be monitored and possibly controlledas well. Designed appropriately, the measuring probe 16 could be used todetermine the type and/or amount of existing bacteria and toindividually determine the type and dosage of the degerminating agent tobe infused and to individually determine the time for the back-flushprocess.

The back-flush valve 11 is opened at first to flush the entire linesystem after turning on the treatment unit. The supply valve 4, which isthe greatest distance away from the sterilization unit 8, issubsequently opened to flush for a sufficient period the feed line 2,the feed line section 2 a and the back-flush line section 10 of thedental instrument 1 that is the greatest distance away from thesterilization unit 8, as well as the return line 10 with its back-flushvalve 11. Now, the supply valve 4 of the first dental instrument 1 willbe closed again and the supply valve 4 of the next dental instrument 1is opened. During this flushing process, only the volume in therespective feed line section 2 a and the one in the back-flush linesection 10 a has to be exchanged. The process is continued until thefeed line section 2 a and the back-flush line section 10 a of all dentalinstruments 1 have been flushed. It is ensure thereby that the entireline system is supplied with degerminating agents. The above-describedflushing process is repeated in all handpieces or dental instrumentsthat were out of operation long enough relative to a period ofstandstill best suited for the degerminating agent.

Bacteria growth can be prevented in the entire line system of thetreatment unit in a simple but reliable manner with the above-describeddevice whereby the entire line system is flushed with the treatmentliquid into which degerminating agents are infused at a relatively lowdosage.

1. A device for feeding a treatment liquid into medical appliancescomprising an outlet opening for said treatment liquid, said devicecomprising: a feed line for said treatment liquid, means to introducedegerminating agents into said treatment liquid, at least one switchvalve disposed upstream from the outlet opening onto which said feedline is connected, wherein a back-flush line with at least oneback-flush valve is connected to said switch valve, and wherein areservoir is provided for said treatment liquid, whereby said treatmentliquid is transported from said reservoir with the aid of a pump, andwherein the back-flush line is connectible alternatively via a drainvalve to one of a drain and to said reservoir so that the treatmentliquid is pumped into said drain, or is circulated from said reservoirthrough said feed line to said switch valve and through said back-flushline again into said reservoir.
 2. A device according to claim 1,wherein said switch valve and said back-flush valve together act as athree-way valve disposed upstream from said outlet opening.
 3. A deviceaccording to claim 1, wherein said back-flush valve is arranged in theback-flush line and wherein said switch valve is pressure-controlled sothat it opens up while said back-flush valve is closed based on the backpressure developing in said back-flush line and whereby said switchvalve closes while said back-flush valve is in an open position.
 4. Adevice according to claim 1, wherein said switch valve comprises anon-return valve.
 5. A device according to claim 1, wherein means todetermine the type and/or amount of existing germs is provided todetermine the type and dosage of the degerminating agent to be infusedas well as the time for the back-flush process.
 6. A device according toclaim 1, wherein means are provided to determine the concentration andthe type of the degerminating agent in the treatment liquid so that thedosage of the degerminating agent infused in said treatment liquid maybe monitored and controlled.
 7. A device according to claim 1, whereinsaid reservoir has a dosage device dedicated for at least onedegerminating agent so that said degerminating agent can be added to thetreatment liquid in said reservoir.
 8. A device according to claim 1,wherein a sterilization unit is disposed upstream from said reservoir.9. A device according to claim 1, wherein a drain valve is providedthrough which said reservoir can be emptied directly.
 10. A deviceaccording to claim 1, wherein a plurality of handpieces of the medicalappliance are connected parallel to said feed line for the treatmentliquid via respective supply valves, and wherein back-flush linesections extending from switch valves of the individual handpieces leadinto said back-flush line.
 11. A device according to claim 10, whereinsaid handpieces respectively have back-flush valves.
 12. A deviceaccording to claim 10, wherein a common back-flush valve is provided insaid back-flush line for all connected handpieces.